Railway traffic controlling apparatus



Oct. 9, 1923.

1,469,799 R. A. MCCANN ET AL RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Oct. 17, 1922 3 Sheets-Sheet 1 INVENTORSI B-MQ Cqnn, 1.. V-Aa was,

a; a Val/.1422 w ATTORNEY Oct. 9, 1923.

1,469,799 R. A. McCANN ET AL v RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Oct. 17. 1922 3 Sheets-Sheet 2 Oct. 9, 1923. 1,469,799

R; A. M CANN ET AL RAILWAY TRAFFIC CONTROLLING APPARATUS Filed Oct. -17, 1922 I5 Sheets-Sheet 5 INVENTORSI: A. C, Cqa-nn, z. 1/. ,Le w/s,

v 0c mam WMTTQRNEY Patented Oct. 9, 1923.

- UNITED STATES PATENT OFFIQE.

RONALD A. MceAN orswIssvA-L AND LLOYD v. LEWIS, OF 'nnenwoon BoRo Gn, PENNSYLVANIA, ASSIGNORS TO THE UNION SWITCH & SIGNAL COMPANYQOI SWISSVALE, PENN YLVANIA, A CORPORATION or PENNS ANIA.

RAILWAY-TRAFFIC-CQNTROLLING APPARATUS.

'Application fileii October 17, 1922. Serial o. 595,068.

To all whom z'tmay concern:

Be it known that we, :RON-ALD A. MoCAN-N and LLoYD V. LnwIs, citizens of the United States, residing at Swissvale and Edgewood' Borough, respectively, in the county of Allegheny and State of :Pennsylvania, have invented certain new and useful Improve.

ments in Railway-Traific-Controlling I Ap- I paratus, of which thefollowing is a;speci-.

. when placed end-to endin the order named,

illustrateone form of apparatusembodying our invention, Fig. '2 is a anew similar to a portion of 1 but illustrating a modification of our invention.

Si1nilar reference. charactersrefer to similar parts in each of the views. a 7

Referring first to Figs. 1 and 1?, the reference characters 2 and 2 designate. the track rails of ,a single track over which traflic moves in both directions,- the stretch of track shownin the drawing including a passing siding G The track rails are divided by insulated railjoints 3 into .a plurality ofsuccessive. track. sections 4fn56 6-7, etc. I Traffic along theportion of track shown in the drawing from left tonight. is gov.-

erned by pluralityc f roadside signals S, S and. 8, while trafficalon-g this same stretch fronrright to'left is overned by a plurality- 0f similar signals d n S and S As here shown, each signal is located adjacentthe-junction ot two .track sections.

although this exact location is not essential. a h S gn l th f rm, illu ted nth r wing i a the re -re iti semina s ime .arraasei ind ca ep7, f a t n a med- T k. s c io i pr vid d wi h fack rc sompr sina int rn er sure yns a terna ing cemen ate h t a rails adja -t.-t licmiddleofthe section ,andtwo track relays T and T normally connected.

with the track rails adjacent the two ends ot thesection respectively. In the arrangemerit-shown n F g. 1 a-transformer 86.con-' stitutes the immediate supply of alternating current to the track. rails at the middle of this section, the secondary of this transformer being directly connected across the rails of the section. The primary oftrans; former 86 isprovided with two sources of; current, one of which is a-transformer 8f, the secondary of which is connected with the primary oftr-ansforme'r 8 6 through-front contacts of a third track relay B, which track relay is'connected across the rails of section 56 adjacent the middleof the sec.- tion, an impedance being included (be-- tween this .relay and one of the track rails; The primary of transformer :87 is connected with a transmission line L to which altermating current tis ,const antly supplied by a generator 8. The other means for supplying current to the primary of transformer 86 will be explained, hereinafter. 7

Track section 6-7 is provided with; 51 track circuit which is similarinall respects to the track circuit for .section 5 6 andthe samething is true of the partial track-sec tion shown to the right of point 7. Y

The track section .-l5, which includes the siding G, is provided with a special ,traelr circuit comprising a trackrelay T normally connected across the rails adjacent the righthand end of the section, a track relay- T constantly connected across the rails ad 1' acentthe left-hand endof the gection and a the rails at the same point as track relay T,

We have stated that. certain of the track relaysare normallyconnected with therails otthe severaltracl: sections. As will appear hereinafter these track relays are at times disconnected from the rails and sources of. alternating current are connected to the rails their places for reasons which Wlll' transformer C normally connected across Sflthe caution circuit is from the secondary of transformer U through wires 9 and 10, left-hand point of contact 11 of relay A, wire l2, operating mechanism of signal 5 wire 13, left-hand point of contact 14 of relay A and wires 15 and 16 to, the secondary of transformer U This circuit is closed 7 through wires 9 and 10, the right-hand point providing the relay with a second winding which is constantly supplied with alternating current in accordance with the usual practice. The second winding is omitted from the drawing tosimplify the disclosure;

The proceed indication circuit for signal- S is from the secondary of transformer U,

of contact 11, wire 17, operating mechanism of signals wire 13, right pointjof contact 14,"and wires 15 and 16 to the secondaryof transformer U". It willbe seen that t is proceed circuit is closed only when relay A is energized by current of such I polarity that the contact fingers of this relay are swung tothe right, which current we will term currentof normal relative polarity.

' with alternating The'primary of transformer U is supplied mission line L.

The control of each'signal S by its associated line relay A is the same as the control of signal S by relay A Line relay A is provided with a controlling circuit which is'as follows: from the secondary of transformer U", throughv wire 18, pole-changer P operated by signal Sflfwires 19 and 20, contact 21 of line relay A, wires 22 and 23, contact 24 of track relay T", wire 25, contact 26 of track relay T Wire 27 winding of relay A wires 28 and 29, pole-changer Pfl'and wire 30 to the secondary of transformer U. It will be noted that this circuit is controlled by both track relays T and T for track section 5-6, so that thefcircuit will be'open when any part of this section is occupied by a train. "The circuit is also controlled line relay A so that the circuitfis likewise open whenever the latter line relay is de energized. The circuit furthermore includes pole-changer P which is operated by signal Shin such manner that whenthe latter signal indicates proceed or cau- T tion the current supplied to relay, A is of normal relative polarity but that when sig nal S indicates stop the current. supplied to r elayA is of reverse relative polarity.

" The-"circuit for relay A is provided with current from the trans-' a branch around contact 21 of line relay A, which branch passes from wire 19, through wires 34 and 33, contact 32 of an auxiliary relay X? and Wire 31to wire 23. It follows that when relay X is energized, line relay A is eliminated from the control of the circuit for line relay A 7 The auxiliary relay X is provided with a pick-up circuit which passes from secondary of transformer U,'through wires 18 and 35, back contact 36 of track relay T wires 37 and 38, contact 59 operated by signal S, wire 39, winding of relay X and wires 40 and 30 to the secondary of transformer U.I

Contact 59 is closed only when signal S? indicates proceed or caution, and so relay'X can be picked up only when a train moving toward the right enters section 6? and then only if signal S is in one of the positions specified. As soonas signal S moves beyond the caution position in responsefto the entrance of such train into the section,

the pick-up circuit forrelay X is open, but

in the meantime a stick or holding circuit has beenclosed, which circuit is from'the secondary of transformer U through :wires 18 and 35, back contact 36 of track relay T', wire 41, contact 42 of relay X, wire 43,

winding of relay X, and wires 40 and 30' to the secondary of transformer U. For reasons which will be explained hereinafter, track relay T remains open until the rear of the train passes out of section 6 7-and so i it will be seen that relay X remains closed as long as section 6 .7fis' occupied'by any portion of the train.- y

The control of each line relay A, A, A

relay A.

When signal S indicates proceed or caution the line relay A is provided with and A is the same as the control of line a normal circuit which passes from the' secondary of transformer U, through wire 44, contact 45' closed when signal S indicates proceed or caution, wires 46 and 47, contact 48 of track relay T", wires 49 and 50, contact 51 of track relay T, wire i 52, contact 53 of track relay T, wire'54,

winding of relay A, wires 55, 56 and 57 to the secondary of transformer U. When signal S indicates stop the circuit for line relay A includes thesecondary of the reversing transformer H whose primary is supplied constantly with energy from transformer U* over wires 44 and 57 This latter circuit is termed the reverse circuit 'of- A,

and passes from the secondary" of H through the contact of circuit controller 45 closed when signal S indicates stop, 7

wires 46 and 47, contact 48, wires 49 and 50,

contact 51, wire 52, contact 53, wire 54,

winding of relay 'A, wires 55, 56 and 57 ,to

the secondary of transformer H In solfar V 'as the circuits just traced are concerned," the signal S will indicate stopwhenever" any one" of the track relays T T and-T are open, will indicate caution when these" 7 relays are closed and signal S indicates stop, and will ndicate proceed when these relays are closed and signalS indicat es caution or proceed. "These circuits are provided witha branch around contact 48 of re'lay T however, which branch passes from wire 46, through"wireet6 contact 8'1 of auxiliary relay X and wire 82 to wire 50. The control of relay X is similar tothe control of relay X and inasmuch as relay 'X 'is' closed; when a train moving toward the left passes slgnail S it will be seen that a'tsuchtime signal S will more totl1e c'aution position as soon as therear 7 contact89 ofrelay' X and wire 91 to'wire of transformer U.

senses-thetranspires of tl'ie tr'ain-passes S and tothe' proceed position-"as soon as signal S movesto the caution position; while-it T i's'open' due'to a=train approaching S from the left, both Y S- and-S will indicate stop;

The: controlo'f lin'erelay A is similar to' the-"control of linetrelay A and, consequently, further explanation will not be necessary.

The'circu'it for line relay A isfrom the secondary of transformer U throughwire 60, contact 61 of a relay wires 62an'd 63,- contact 641 of track relay T wire 65, contact 66Tof track relay T wire 67, winding of relay-A, wires 68, 29 and 7 0, contact 71'of relay and 'wire rto the'secondary Thecontacts 61 and 71 of relay V which are included in this circuit, constitute a pole changer by virtue of whichcurre'nt of normal or reverse-relative relay VV is closed or open.

Relay W is normally closed by virtueof:

polarity is supplied to relay A accordingasa circuit which passes from the secondary of transformer U through wlres'tt and'72,

()ne branch passes from wire 44, through wire 160,'- contact 161 operated b'y signal S wires 162 and 75 to wire 76 -The other branch-passes from wire 44 through wire 90,

76 It will be seen, therefore, that relay V7 is die-energized as soon as relay A is opened by atram movmgtoward the right,

but that when a train passes signal-$11102 ing towa'rd the' 'le-ft, relay VV will become closed at once. that wlien'signal S is placed at s'topby train moving'toward' the' right; signals is at caution and signal S- left, signal sue-camera the proceed pestnon: S6 to" he c signal S The result of" this control is ls'at caution or stop, but that" when a train moves I toward the The control ofre'lay W associated with is the same as the control of relay although the signal which is controlled by relay is not shown in the drawings.

The apparatus shown in the present application is intended for co-operation with suitable train-carried governing mechanism for the control of the speed of the train. This train-carried governing mechanism is controlled in part by the track circuit current through the medium of receiving appliances at the front end'of the train, and so it is obvious that a source of track circuit current must always beconnected across the track rails ahead of the train. In so far asthe apparatus thus far referred to is con ce-rned,it will be seen that when a train moving toward the" right enters section 56it willreceive a-lternating track circuit current until-the point is'reached at which relay'B" opens; beyond this point, a source of current isp'rovided in advance of the train, however, by the apparatus which we will now explain. Referring particularly to track section 5+6, relay R at'th'e right-hand end'ot this section'is'a'repeater of the auxiliary relay X at the left-hand end, and similarly, relay B at theleft-hand end serves as a repeater for'auxiliary relay X at the right-hand end. Both of these repeater relays are normally open. Relay R is provided with a circuit which passes from the secondary of transformer U through wire 60, contact 61 of relay wires 62 and 92, front point of contact 93 or relay X wire 9 1, back point of conta'ct'95 of relay X wire 96, back contact 97 of track relay T, wire 98, winding of relay R and wires 99, 29 and 70, contact 7-1 of relay and wire 55 to the secondary of transformer U Inasmuch as relay X is closed only when a train mov- 'ing toward tlie'rigrht enters section 56, it

will be seen that this is the only condition under which repeater relay R can be closed. Relay R will not close" however, until the train reaches such a point in the section that track relay T* opens, and we will assume that this occurs before the middle track relay B- op'ensQ V v 7 When relay R closes, it performs two functions-z First, itscohtacts- 100 and 101 disconnecttracl-r relay T from therails of sec'tion-5"6; and connect the secondary of transformer C 'with the track rails in the place of the track relay. Second, it opens thenormally closed circuit for the primary of transformer 86, which circuit passes from the secondary of transformer U through wire' 6O,conta c t' 61 o'frelay Vi, wires62, 63 and102,-back Contact 103 at repeater relay Rfi wire 10%, primary ottransiorme'r '86-, wire- 105, each contact 106 of repeater relay wires 107, Q-Qand '70, contact 71-05 relay an 55 to trans fo '"iner U The circuit" lit) contact- 117 of relay T.

through wires 109 and 108, contact 110 of.

relay X, wire111, back point of contact 112, of track relay T, wire 113, back point of contact 11 1 of track relay T wire 115, Winding ofrelay R, and wires 116, 55, 56

and 57 to transformer U. Vhen relay R is closed, it disconnects track relay T from therails of section 1-5 and connects transformer C with these rails. The operation of the apparatus thus far described. is as follows:

of track-shown in the drawing. While such train is, still in the portion of track to the left of signal S it will, of course, have placed the latter signal at stop,'so that the circuit for line relay A is open at contact 48 on track relay T Signal S is therefore, in the stop position and relay W is open, because its circuit'is broken at contact 78 on signal S The result of this is thatsigna'l S is. in the caution position, because relay A is supplied with current of reverse relative polarity. As the train passes signal S it opens track relay T", which in turn opens line relay A, so thatsignal S moves to the stop position. The opening of traclr relay 'l also closes auxiliary rela the latter relay subsequently remains closed as long as relay T is open, because the hold- X" and ing' circuit for. relay X includes a back Track relay T also opens as soon as the train enters section l5, because track ransformer C, the only source of track circuit current for this section is immediately shunted. Repeater relay R is therefore closed as soon as the train enters the section and so track relay T is disconnected from the rails and transformer C is connected with the rails instead. The connection between transformer 'C and the track rails includes a back contact 118 of'relay X, so that as long as the train occupies section 4l-5 this transformer is disconnected from the rails in the rear of the train... When the train passes out of section 4-5. the current from transformer C energizes track relay lT over the track circuit, and the consequent closing of this relay opens relay X,-which in turn opens relay R', whereupon transformer C is disconnected from the rails and track relay T9 is re-connected with the right-hand end of section et-5. The opening of relay X of When the train enters section 5-6, track:

relay T is de-energized, theauxiliary relay X closes and. while the train is proceeding through the left-hand portion of this section it receives track circuit current from transformer 86. After reaching a point near the middle of the section, however, track relay T at the right-hand end opens, whereupon. relay R closes, thereby replacing track relay T with transformer C and also opening the branch primary circuit for transformer 86. Subsequently the middletrack relay B opens and thereby disconnects transformer 87'from theprimary of transformer 86,"so that the supply of current to the middle of the section is discontinued. The train re- 4 ceives track circuit current, however, from \Ve Wlll first assume that a train moving toward the right passes through the stretch transformer C until it leaves section 5 -6;

While the train is in the right-hand half of section 5 -6 there is no source of track circuit current connected with the railsin the rear of the train, because the branch primary circuit for transformer 86 is open at repeater relay R and the secondary circuit for transformer 87 isopen at the contacts of relay B; relay B remains open, of

course, because there is no track circuitcurfrom the rails and track relay T) is again.

connected. therewith. It also closes .the

branch circuit for'transfor'mer 86 so that current is again supplied to the middle of the sectlon, closmg-B, connecting 86 again direct to source 87. Relay T closes as soon reversing transformer H contact 58, Wire; 163, contact 164 of relay X wires 165 and 166, thence over the contacts of T and T'- to relay A, so that relay A is energized in the reverse direction and signal 31 moves to the caution posit-ion.

As soon as the train leaves section 5 -6, relay T will be closed; the circuit of A is however not opened thereby, because the branch through contact 1640f X is replaced by the branch from contact 58 through contact 167 of relay T to Wire 166'.

lll)

Relay A will now be energized with -cur-f rent of reverse polarity over T line wire 25, relays T and X and pole-changer P so that signal S will indicate caution. Relay A Will now receive currentof. normal polarity from transformer U over cont-actv 58 operated bysigna'lS so that signal S willindicate procee'd. i

The operation of the apparatus as "the train passes through: section .6 7 will-be understood from the foregoing without fur ther explanation.

During the movement of a train toward the left repeater relay R closes as thetrain approaches the middle of section 5'6 and this relay,.ofcourse removes track relay T from the track circuit and places transformer C therein. As suclrtrain enters section 4-5, it opens track relay T, but has no effect on relays: R and X, and so transformer G supplies track circuit energy to the train throughout the entire length of the section.

The apparatus shown in Fig. 1 also includes means for at times supi iilying what we will term. a local current to" the track rails, which current flows in the same direction in the: two track ra'ils or, in other words, flows through these rails: in multiple. The pur pose of this current will be explained hereinafter. Considering'section 5'6,. for example, when a train moving toward the right enters. this section; the opening of track relay T closes the following. circuit: from the secondary of transformer U,

through Wire L8, pole-changer P wire 1' 9 Wire 20, contact 21 of line relay A wire 22' i and 23, contact :24:- oftrack relay T wire25,,

back point of :contact26uoftrack relay T wire 119'; back. point of contact 120 of repeater relay R twine 121, primary of a trans former K wires122,.28 and 29, polechanger P1 and. Wire 30 to-itransfonner U The secondary'oftransformer K then supplies current to the track rails of section 56 between a resistance. J and aires'istance J the circuit being" from-the middle point of resistance J i, wire 5126, the secondary of transformer K wire-1'23, contact 124 ofrelay X Wire. 125 to resistance J, then through theltrack rails '2 and 2 in multiple circuit fol-transformer K? i clude 9 1 changer which is ope-rated by signal S it will be seen that the local current thus supplied to the track rails will be of normal or reverse relative polarity, depending on the position of signal S W'e will assume that when signal S indicates proceed: or caution former U", through Wire 18', pole-changer P wires 19, 3i and 127, front point of contact 128 ofrelay R3,. wire 129,. primary of transformer K, wires 130 and 29, polechanger P and wire 30 to the secondary of transformer U. If signal S indicates proceed or caution, the secondary circuit for transformer K 'is closed to supply local cur rent to thetrack rails from resistance J to resistance J this circuit being from the middle point of resistance J through wires I34 and 133, contact 132, wire 131 to the secondary of transformer K thence over wire 1 35 to resistance J and over the track rails in multiple to J This currentwill be of normal relative polarity because the primary circuit for transformer K includes p0lechanger P and this pole-changer delivers ciu'rent of normal relative polarity when signal S indicates proceed or caution. If signal 3 indicates stop, the. secondary circuit for transformer K will be from J 5 to 5* instead offrom J to J this circuit being from the middle point of J 5 over wire 136, wire 131, the secondary of K wire 135 to resistance J*, the rails 2- and 2*" in multiple, to-resistance This current will be of reverserelative polarity because pole-changer P is reversed when contact 132 is reversed.

It will be seen from the foregoing that when atrainmoving toward the right passes through sectioni56 it will receive local current of normal relative polarity throughout the entire section if si gnal's' indicates proceed or caution, or local current of reverse relative polarity from. resistance J to resistance J if signal S indicates stop.

It should-here be pointed out that the apparatus shown in the present application is intended for co-op'eration with train-carried mechanism so constructed that when the mechanism receives track circuit current as well as local current. of normal relative polarity the train may'procced at full speed; when the train carried mechanism receives track circuit current and local current of reverse relative p'o'larityyth'e train may proceed at an intermediate speed; and'when the train receives track circuit current alone it may proceed at a low speed. In all three instances the brakes will be applied if the train exceeds the speed permitted by the characteristicsof the currents receivedfrom ance J to resistancewl if signal S indicates stop. The apparatus and circuit'sfor SHDDlylH'Q current during the passage of a train'moving toward the left are the same as 5 that just described for the passage of a train moving toward'the right with one exception. When a train; is in section 56 approaching S its local circuit is energized from transformer K whose primary is controlled by the pole-changer contacts of relay W It now, the-train passed signal S at clear, and an opposing train should cause signal S to go to stop, the main circuit for relay W would be opened thereby; the deenergization of W and the consequent reversalof the local circuit under the train is prevented, however, because of a branch circuit for relay W. This branch circuit is from transformer U through wires 9, 83, stick contact 84 of relayVV", wires 85, 77, contact 78, wire 79, relay W wires 80 and 16 to transformer U The local circuit is therefore, not reversed until signal S goes to stop, in which case this holding circuit for relay W is opened at contact 78. Section 67 and the portion of the section shown to the right of point 7 in Fig.1 are equipped with apparatus similar to that just described for section 5-6 for supplyingloc'al current to the track rails. V

The apparatus shown for supplying local current to the rails of section 45 is as follows: 7

Assuming that a train moving toward the right enters this section, the closing of relay.

X and repeater R willclose a circuit from resistances J 3 to-J for section 45, this circuit being from the middle point of resistance J wires 140 and 139, contact 138, wire 137, the secondary of transformer K wire 148, contact 147 of relay R wire 146, contact 145 of relay T", wirel lt, contact 143 of relay X wires-142 and 141 to resistance J, thence over thetrack rails of section 45 in multiple-to resistance J. Inv tracing this circuit we have assumed that signal S indir cates proceed or caution. This being so, it will "be noted that the local/current is supplied to section l -5 throughout the entire length of this section andfor reasons which we willrexplain hereinafter this current is of normal relative polarity owing"to the position of contact 58 which controls the polarity' of the primary circuit of transformer K If signal S isat stop, however, then the circuitfor the secondary of transformer K will be from llioverwire 149 tov contact 138,, instead of from J to 138. Under this condition local current is supplied only from resistance J at an intermediate point in the "block, to 'J at the entrance end of the block, and owing to the fact that contact58 is reversed ,this current will be of reverse relative polarity. V

VVhen-a traln moving toward the left enters section L5, the opening of track relay T will close at contact 145 the secondary circuit for transformer K thereby supplying local-current of normal relative polarity of the 87, the

section in either direction.

throughout the length of the section if signal S indicates proceed or caution, and local current I of reverse relative polarity from resistanoeJ to resistance J of section 4-5 if signal S indicates sto The secondary circuit for transformer I 8 is similar to the circuit traced hereinbefore for transformer K and will be apparent from the drawing without further explanation. 1

The polarity of the current supplied to the local circuit for section 4-5 during a train movement to the right is controlled by contact 58.0perated by signal S and byreversing transformer H the operation of these parts being as follows: WVhen signal S is in the proceed or caution position the right-hand terminal of the primary of transformer K is connected with the secondary of transformer U byme-ans of contact 58, and wire 9, the left-hand terminal of the primary of. K being connected with the secondary of U by wire 16; current of non mal relative polarity is then supplied to the local circuit for section 45. W'hen signal S indicates stop, however, the contact 58 breaks the direct connection between transformers K and Uf, and contact 58 then connects the primary of K with the secondary of transformer H the primary of transformer H isconstantly connected with the secondary of transformer U The right-hand terminal of the secondary of U is connected with the right-hand terminal of the primary of H by wire 9 and the right- The polarity of the current supplied to the 7 local circuit for section .4-5 while a train is moving toward the left is simarily controlled by a contact 45 operated by signal S and by transformer H Referrmg now to Fig. 2, we have here shown a modification of the apparatus associated with section 5-6, which apparatus Y is the same as that shown in Fig. 1 except as to the means for disconnectlng the source of track circuit currentfrom the =middleof 1 the section, and except as to certain details concerningthe circuits for the local current. In Fig. 2 the track circuit current is supplied to the secondary of which is connected with the rails through back contacts of relayB Relay B is normally open but is closed whenever a train passes through the Assuming for example, that atrain is moving toward the right, when this train reaches such point that it opens track relay T, relay B and rails at the middle section 5-6. by atransformer primary of which is constantlyj connected with the transmission line L j and the i repeater relay R becomes closed by virtueof b UL) former U course disconnects transformer 87 from the a circuit which passes from the secondary of transformer U through wire 60, contact 61 of relay lV, wires 62 and 92, front point of contact 93 of relay X wire 94, winding of relay B wire 94-, back point of contact 95 of relay X wire 96, backcontact 97 of track relay T, wire 98, winding of repeater relay R wires 99, 29rand 70, contact 71 of relay 9 W, and wire 55 to the secondary of translVhen relay UB closes it of rails and the closing of track relay T connects transformer C with the rails at the end of the section, so that the train is sup-' former 87 is again connected with the rails at the middle of the section and track relay T is again connected with the rails at the right-hand end of, the section. The two track relays then become energized from transformer 87 and so the parts of the track circuit are restored to their original conditions.

hen a train moving toward the left passes through section 56, relays B and R are closed by virtue of a circuit which is similarto the circuit previously traced for B and R and, in fact, the operation is symmetrical-in every respect to the operation of the passage .of' a train moving toward the right. r

Local current is supplied to the rails of section 5 6 from resistance J to resistance J by a transformer K and from resistance J to resistance J by a transformer K The secondary circuit for transformer K is from'resistance J wire 151, the secondary of K through wire 150, resistance J, track rails 2 and 2 to ,resistance J lVhen a train moving toward the right passes through section 5-6, the primary circuit for transformer-K is from the secondary of transformer U through wire 18, polechanger P wires 19 and 29, contact 21 of relay A, wires 22 and 23, contact 24 of track relay T, wire 25, backpoint of contact 26 of track relay T wire 119,-.back point of contact .120 of repeater relay R wire 121, primary of transformer :K wires 122. 28 and 29, p'ole-changerP and wire 30 do the secondary of the transformer U This circuit is closed when track relay T is closed and track relay '1 is open,-and,consequently, transformer K suppllescurrent to the rails' only until the train reaches such point that-it opens track relay T*. This current will be of normal relative polarity when signal S indicates proceed or caution,

andof reverse relative polarity when such signal indicates stop.

- The secondary circuit for transformer K passes from resistance J wire 155, secondary of K wire 156, resistance J, track rails 2 and 2 to resistance J Vi hen a train'moving toward the right reaches such point that track relay T opens, the repeater relay R becomes closed by virtue of a circuit traced hereinbefore, and if signal S indicates proceed of caution, local current of normalrelative polarity is then supplied to the primary of transformer K through a circuit which passes from the secondary of transformer U, through wire 18, polechanger P wire 154, contact 153, wiie152, front point of contact 128 of'repeater relay R, wire 129, primary of transformer K, wire 29, pole changer P and ,wirer30 to the secondary of transformer U If signal indicates stop, however, the primary circuit-for transformer K is opened at contact 153 operated by this signal, and so there is no local current supplied to the rails between resistances J and J in section 56.

'The operation of the apparatus during the passage'of a train moving toward thelcft will be apparent from the foregoing without further explanation.

Although we have herein shown and described only two forms of apparatus embodying our invention, it is understood that various changes and modifications-may be made therein within the scope of the appended claims 'without departing from thespirit and scope of our invention.

Having thus described our invention,

what we claim is:

dle of the section and two track relays connected with the rails adjacent the two ends of the section, and means controlled by said relays when affected by a train in the section for disconnecting from the rails the track relay in advance of the train and connecting a source of alternating current with the rails in itsiplace.

2. In combination, a section of railway track, atrack circuit for said section including a source of alternating current connected with the rails adjacent the middle of the section and'two track relays connected with the rails adjacent the two ends of the section. and means controlled by said relays when affected by a train in the sectionlfor disconnecting said source of current and the track relay in advance of the" 7 track, a track circuit for said section includmg a source of alternating current connected train from the rails of the section and con- 'necting an auxiliary source of current with .the rails in place of the track relay.

' 3. In combination, section of railway track, a track circuit for said section including a source of alternating current connected with the rails adjacent the middle of the'section and two track relays connected with the rails adjacent the two ends of the section, and means controlled by said relays when affected by a train in the section for dlsconnectlng sa1d source of current from the rails and keeping it disconnected until the train leaves the section.

4.711 1 combination, a sect-ion of. railway with the rails adjacent the middle of the sec-- tion and'two track relays connected with the rails adjacent the two ends of the section, a normally open auxiliary relay at each I end of the section, means controlled by each track relay when opened bya train entering the rails in its place, and means for closing I each repeater relay when the auxiliary relay at the other end of the section and both rack relays are open. 5. In combination, a section of railway track, a track circuit for said section including a source of alterating current connected with the rails adjacent the middle of the section and two track relays connected withthe rails adjacent the two ends otthe section, a normally open auxiliary relay at each end of the section, means controlled by each track relay when opened by a train entering the section at the corresponding end for closingthe auxiliary relay at that end and keeping it closed until-the train leaves the section, two normally open repeater'rela-ys one at each. end of the section and each operated when closed to disconnect said source of current and the track relay associated with the repeater relay from the rails and connect a source of alternating current with the rails in place of such track relay, and means for closing each repeater relay when the auxiliary relay at the other end of the section and both track relays are open.

6. In combination, a section of railway track, two track relays connected with the rails at the ends of said section and a third track relay connected with the rails adjacent the middle of the section, a main source of current connected with the rails adjacent the middle of the section and controlled by a front contact of such relay, an auxiliary source of current also connected'with the rails adjacent the middle of the section, and

the middle of the section and for keeping said auxiliary source disconnected thereafter until the train leaves the section.

7, 'In combination, a section of railway track, two track relays connected with the railsat the ends of said section and a third track relay connected with the rails adjacent the middle of the section, a main source of current connected with the rails adjacent the,

middle of the section and controlled by a front contact of'such relay, an auxiliary source of current also connected with the rails adjacent the middle of the section, and means controlled by said end track relays when affected by a train passing through said section for disconnecting said auxiliary source from the rails as the train approaches the middle of the section and for keeping said auxiliary source disconnected there after until the train leaves the section, and means also controlled by said track relays when affected by a train pass ing through the section for disconnecting the end track relay in advance of the train from the rails and connecting a source of alternating current with the rails in its place.

8, In a railway traffic controlling system of the type comprising a stretch of track divided into sections, a source of alternating current connected with the rails of each section adjacent the middle of the section, two

' track relays normally connected with the rails the same direction, a normally open auxiliary relay for each signal arranged when energized to eliminate the associated line relay from the controlling means for the line relay next in the rear, means for closing each auxiliary relay when a train passes the associated signal moving in the direction in which the signal governs traffic and for subsequently keeping it closed until the train leaves the section governed by such signal;

the combination with the foregoing instru- -mentalities of two normally open repeater relays one at each end of one of said sections and each operating when closed to discon nect the adjacent track relay from-the rails of said section and connect a source of al ternating current with such rails, and means for closing each repeater relay when the adjacent auxiliary relay and the adjacent track its relay are opened and the auxiliary relay at the opposite end of the section is closed.

9. In combination, a section of railway track over which trafiic moves in both directions, means operating when a train enters said section from either end to supply loca current to the rails from the end at which the train enters to an intermediate point in the section, and means operating before the train reaches such intermediate point to supply local current to the rails from a point in the rear of said points to the end at which the train will leave the section.

10. In combination, a section of railway track over which trafiic moves in both directions, means operating when a train enters I said section from either end to supply local current to the rails from the end at which i the, train enters to an intermediate point in the section, said current being of one rela tive polarity or the other according to traffic conditions beyond the section in the direction in which the'train is moving; and means operating before the train reaches said intermediate point to supply local current of normal relative polarity to the rails from a second intermediate point in the rear of the first to the end at which the train. will leave the 'section, or of reverse relative polarity from said second intermediate point to a third intermediate point in advance, of the second, according to trafiic conditions beyond the section in the direction in which the train is moving.

11. In a railway trafiic controlling system I of the type comprising a stretch of track divided into sections, a source of alternating current connected with the rails of each section adjacent the middle of the section, two track relays normally connected with the rails of each section adjacent the two ends of the section respectively, two signals for each section for governing traflic in opposite directions through the section, a line relay for each signal, means for controlling each line relay by both track relays for the associated section and also by the line relay for the signal next in advance governing traffic in the same direction, a normally open auxiliary relay for each signal arranged when energized to eliminate the associated line relay from the controlling means for the line relay next in the rear, means for closing each auxiliary relay when a train passes the associated signal moving in the direction in which the signal governs traffic and for subsequently keeping it closed until the train leaves the section governed by such signal; the combination with the foregoing instrumentalities of two normally open repeater relays one at each end of one ofsaid sections, means for closing each repeater relay when the auxiliary relay at the opposite end of said section is closed and the section is occupied by a train approaching such repeater relay, means controlled by each auxiliary relay when closed for supplying local current to the track rails from the adjacent end to an intermediate point in the section of normal or reverse relative polarity according to traflic conditions in advance of the section, and means controlled by each repeater relay when closed for supplying local current of normal relative polarity to the rails from a second intermediate point in the rear of the first to the end adjacent the repeater relay or of reverse relative polarity from said second intermediate point to a third intermediate point in advance thereof according to traffic conditions in advance of the section.

12. In combination, a section of railway track, a track circuit for said section including a source of alternating current connected with the rails adjacent the middle of the section and two track relays connected with the rails adjacent the two ends of the section, and means controlled by said relays when affected by a train in the section for disconnecting a normally open relay arranged when closed to disconnect said source of current from the rails, and means controlled by said track relays 'when affected by a trainpassing through the sec-- tion for closing said normally open relay before the rear of the train passes said source and keeping it closed until the train leaves the section.

13. In combination, a section of railway track over which traflic moves in both directions, means operating when a train enters said section from either end to supply local current to the rails from the end at which the train enters to an intermediate point in the section, and means operating before the train reaches said intermediate point to supply local current to the rails from a point in the rearof said point to the end of the section under clear traflic conditions in advance but not under unsafe traffic conditions in advance.

In testimony whereof we afiix our signatures.

RONALD McOANN. LLOYD V. LEWIS. 

